Project Summary/Abstract Anorexia nervosa (AN) and bulimia nervosa (BN) are chronic and severe psychiatric illnesses associated with complex physical and emotional sequelae. Long-term studies of eating disorders are few in number and comprehensive understanding of the outcome of these illnesses has been challenged by a lack of an empirically-based definition of recovery. The current application proposes a one-time follow-up investigation of the surviving participants of the Massachusetts General Hospital Longitudinal Study of Anorexia and Bulimia Nervosa 25 years after initial funding for the project by NIMH began in 1987. This study of 246 treatment-seeking women, which included 51 women with AN-restricting subtype, 85 with AN-binge/purge subtype, and 110 with BN, is the only long-term, prospective, naturalistic study of its kind, making it an invaluable resource for promoting our understanding of the natural course of eating disorders. The cohort was interviewed at frequent intervals until 2000 for approximately 10 years of follow-up (median = 9 years, maximum = 12 years). The attrition rate at 10 years of follow-up was 7%. Annual contact has been maintained with the cohort. To date, we have confirmed participation in the proposed follow-up with 155 (67%) of our potentially 230 living participants and we continue our efforts to include an additional 44 subjects (only 31 subjects declined participation). This application proposes to establish an empirically-based definition of long-term eating disorder recovery by examining the predictive validity (comparing the first 10 years of follow-up to year 25) of a series of definitions of recovery that differ on thresholds of symptom severity and duration. The Eating Disorder Longitudinal Interval Follow-up Evaluation (the same interview administered in the initial phase of the study) will be used to gather data on eating disorder symptomatology, comorbid psychiatric disorders, and psychosocial functioning. Cross-sectional validity of recovery definitions will be examined using clinically meaningful indices such as quality of life. Finally, this study will document long-term outcome of eating disorders, including mortality rates, as well as the demographic and clinical predictors of 25-year outcome. The proposed study is uniquely positioned to examine these questions due to the availability of both a detailed dataset documenting the course of eating disorders over 10 years of follow-up as well as a high percentage of participants willing to be interviewed at the 25 year follow-up. Findings from this study will create a framework for the evaluation of current treatment efforts, assist in the design of future treatment studies, inform researchers conducting outcome studies, and provide clinicians, researchers, and patients with important clinical information about the outcome of eating disorders.